This invention relates to liquid contact apparatus used in chemical processing, and particularly to such apparatus in which a vessel contains a plurality of substantially horizontal trays which support a vapor-liquid mixture. In apparatus of this type, liquid is introduced at the upper end of the vessel and it flows down from tray-to-tray, via downcomers. The trays are apertured to provide bubble areas through which ascending vapors can rise to contact liquid and/or vapor-liquid mixtures which are supported on and flowing across the respective trays.
There have been many proposals for improving contact apparatus of this type. However, significant features of the apparatus disclosed in this specification are believed to represent new approaches to the design and construction of such apparatus.
Chuang et al. U.S. Pat. No. 4,504,426 shows gas-liquid contacting apparatus in which downcomers have apertured lower outlet walls. These downcomers, however, discharge directly over apertured areas of the deck therebelow. Such an arrangement can result in undesirable jetting of liquid down from the downcomer apertures through the apertures in the deck therebelow, thus bypassing two subsequent trays and reducing the performance of the apparatus.
A downcomer with an apertured outlet wall positioned over an elevated downcomer seal area is shown in Bentham U.S. Pat. No. 4,550,000. Bentham also has apertures in the elevated downcomer seal area, and this is believed to be detrimental from the standpoint of tray performance.
In U.S. Pat. No. 4,956,127 issued to Binkley et al., FIG. 8 shows a downcomer with an apertured outlet wall, but the downcomer seal area is provided with gas introducing openings located directly beneath a downcomer outlet. Binkley et al. also disclose a channel beam truss which directly supports an elevated upstream panel provided with the downcomer seal area. However, the channel truss is positioned where it inherently obstructs the horizontal flow of gas immediately beneath the truss-supported tray.